Question

How can I create a Standard Deviation calculated field for Average Ratings in tableau?

Answer 1

While the calculated field has aggregation inside,

Tableau doesn't let you aggregate it again.

So, If you  may try using window aggregation, you need to use such as window_Avg.

EXAMPLE:

First Calculation: Profit Ratio

sum([profit])/sum([Sales]) //Aggregate Calculation

Second Calculation: Avg of Profit Ratio

window_avg([Profit Ratio]) //Table Calculation

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